This excerpt taken from this link:
http://www.dnr.state.mn.us/volunteer/janfeb06/raw.html_________________________________________________________
Life Cycle: 1 The adult fluke lives in the digestive tract of fish-eating birds, typically kingfishers or herons. It produces eggs, which pass from the bird in its droppings. The eggs hatch in water, liberating larvae called miracidia that swim around until they encounter a snail.
2 After digging their way into the snail, the miracidia form mother sporocysts. Mother sporocysts produce sporocysts that invade the snail's liver. In about six weeks, each sporocyst produces another form called a cercaria.
3 Cercariae emerge from the snail into the water. They seek out a fish and penetrate its flesh, forming cysts just under the skin and in the flesh.
4 If a bird eats infected fish, the parasites leave the cysts and mature in the digestive tract of the bird, starting the cycle again.
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So, the RES eat the snail while it contains sporocysts, which are not yet harmful to fish. The fish digest it, may release it back into the water, but can't go back into a snail because it is not a miracidia anymore, and can't go into a fish because it is not developed enough to form cercaria. That's what breaks the cycle.
Does this sound right?
Also, what happens if a bass eats an infected BG, do they get the black spots from it? Or is it passed on thru the system like if a bird ate the BG?
